This invention relates to a handheld or immersion blender with a coupling device.
This application claims the benefit of a foreign priority application filed in Germany, serial number 10114373.3, filed Mar. 23, 2001.
A plurality of handheld or immersion blenders with coupling devices are known in the art. Suitable coupling devices are used as a rule to fixedly position a drive shaft, which is connected to a motor part, relative to a tool shaft, which is fitted to an attachment, in the shaft longitudinal direction, thereby enabling a torque to be transmitted from the drive shaft to the tool shaft and hence to a tool of the attachment. In this arrangement the coupling device has one coupling half fixedly connected with the motor part, while the other coupling half is fixedly connected with the attachment. One known type of connection in this context is a threaded connection of the two components needing to be connected.
A further coupling device is disclosed in FR 1467108, for example. In a handheld kitchen appliance according to this disclosure, a mixer in the form of an attachment is plugged onto the elongated housing of a motor part. On this appliance the tool shaft is held in axially fixed position relative to the drive shaft by means of the stationary housing part of the attachment. Said housing part is connected to the stationary housing of the drive part by means of a snap lock. The snap lock is formed by an arrangement of holding elements on the material, which under spring pressure act inwardly in the direction of a circular receiving opening. The cylindrical coupling section of the attachment has a circumferential groove within which the holding elements engage. The tool shaft itself is inserted by its geared coupling end into a registering coupling gearing of the drive shaft. The coupling locator is formed by an internally geared sleeve. The attachment is released by pressing an ejection device which is constructed on the housing of the drive part in the form of a push-button and recovers the holding elements from the groove, thereby releasing the attachment. This also results in the geared shaft end of the tool shaft being pushed out of the coupling device.
Another coupling device for a kitchen appliance is described in EP-0 692 215 A1. This specification discloses a handheld blender in which a tool shank containing the tool shaft is detachably connected to the motor part of the handheld blender. For this purpose provision is made on the motor part, perpendicular to the drive shaft, for an approximately U-shaped expansion clamp that engages in a mounting groove of the tool shank. The free ends of the expansion clamp are in engagement with expansion surfaces. To release the connection between the motor part and the tool shank the expansion clamp is displaced by means of a push-button. The free ends then slide along the expansion surfaces, causing the legs of the expansion clamp to be pressed apart so that they leave the mounting groove. The connection between the motor part and the tool shank is thus released, enabling the parts to be separated from each other. The arrangement of the expansion surfaces required for spreading the expansion clamp apart and of the push-buttons required for actuating the expansion clamps represents a not insubstantial effort in terms of parts and assembly.
Finally, a further coupling device for a kitchen machine is disclosed in German Utility Model DE 200 06 028 U 1. In this disclosure the connection between the motor housing and a shank part is effected by means of a holding element which is made of an elastic material, preferably plastic, and essentially forms a frame with one longer and one shorter axis. It is thus possible to establish a clamping connection between the housing parts, which is releasable by actuating projecting push-button elements. With this connection the stationary housing parts are held in axially fixed position in the shaft longitudinal direction. The shaft torque of the drive shaft is transmitted to the tool shaft via a geared coupling.
A disadvantage of the described coupling devices for kitchen machines is, on the one hand, their elaborate operation, so that with threaded connections, for example, there is always a risk of the threaded components becoming skewed, and, on the other hand, their high number of moving parts, as is the case with coupling connections having separate holding elements, helical springs and actuating push-buttons, for example.
It is an object of the present invention to provide an improved handheld or immersion blender comprising a coupling device. Coupling and decoupling an attachment to and from a drive part should be easy and require no major force. Such a coupling device should also afford simple and low cost manufacture.
This object is accomplished by a handheld or immersion blender incorporating the features of patent claim 1. Advantageous embodiments of the invention will be described in the subclaims.
An improved handheld or immersion blender is made available by the embodiment of the invention with the features of patent claim 1. Coupling and decoupling an attachment to and from a drive part can be effected readily and without any major force using a simple click-in/turn-out motion. In axial direction the upper coupling part is axially locked with a simple snap action of the holding lugs in recesses on the inner circumference of the lower coupling part. With the coupling of the handheld or immersion blender of the invention requiring only a small number of components and with no need to fit any additional actuating elements, its manufacture is straightforward and economical. An essentially smooth and washable housing construction is also possible as the result.
It is also conceivable, of course, to fit the holding lugs to the lower coupling part and to provide the recesses on the upper coupling part, without departing from the spirit of the invention, i.e., the result is an equivalent solution.
An advantageous embodiment of the invention is provided by the features of patent claim 2. In this arrangement the ramp is constructed as a steadily ascending bead. Hence when the upper coupling part is inserted in the lower coupling part, for example, the holding lugs are able to slide along the ramp, with the holding lugs being previously pressed resiliently inwardly in radial direction in order to enable insertion in the first place.
An advantageous further development of patent claim 2 is provided by the features of patent claim 3. This shape design guarantees, in surprisingly simple manner, that the holding lugs lock into place reliably, regardless of the direction from which they approach the lug receiving socket.
An advantageous further development of claim 2 is also provided by the features of patent claim 4. Hence when the two coupling parts are twisted relative to each other it is possible to move them reliably in axial direction, meaning it is possible to separate the two parts.
The features of patent claim 5 enable a reliable locking action to be achieved on account of the hook engagement in the undercut of the holding edge in the lug receiving socket.
Yet another advantageous further development of patent claim 2 is provided by the features of patent claim 6. Simple decoupling is thus possible, for example, when the holding lugs lie at the ends of the U-legs.
Finally, still another development of patent claim 2 is provided by the features of patent claim 7. Provision can thereby be made for the coupling device to be axially locked as soon as the holding lugs are positioned underneath the vertex of the ramp.
A further advantageous embodiment of the present invention is provided by the features of patent claim 8. The sliding movement of the holding lugs along the ramp is thereby facilitated.
Of particular advantage is an embodiment with the features of patent claim 9. It enables the holding lug to be locked in the holding edge of the lug receiving socket.
Yet another advantageous embodiment of the present invention is provided by the features of patent claim 10. In this embodiment the wave shape and the ramp, which is defined by the lug receiving socket, are coordinated to enable the coupling connection to be decoupled by a simple xe2x80x9cturn-outxe2x80x9d action. Furthermore, a suitable wave shape defines the position of the upper coupling part relative to the lower coupling part in the locked state, i.e., a fail-safe function is established.
A further advantageous embodiment is provided by the features of patent claim 11. It facilitates the processes of locating the upper coupling part centrally relative to the lower coupling part and relative twisting.
Another advantageous further development of the embodiment of patent claim 11 is provided by the features of patent claim 12. It is thus possible to manufacture the part as a simple and low cost injection molding, which can be finish-machined as and when required and has resilient holding lugs.
A further advantageous embodiment of the present invention is provided by the features of patent claim 13. A low-cost, washable, hygienic and impact-resistant construction is thus possible. It will be understood, of course, that other suitable materials may also be contemplated.